Chainsaw and drive system therefor

Abstract

A chainsaw and a drive system therefor are provided. The drive system includes a motor operably coupled to drive a motor shaft and an output drive operably coupled to an output shaft. The motor shaft and the output shaft are mechanically coupled to one another by a transmission system to transfer energy from the motor to the output drive. The motor and motor shaft are coupled to a housing. The transmission system allows the output shaft to selectively change positions along a circumferential direction relative to a rotational axis of the motor shaft to selectively loosen or tighten a connection of the output drive to a chain at a guide bar.

What is claimed is: 
     
         1 . A chainsaw, the chainsaw comprising:
 a guide bar configured to receive a chain; and   a drive system comprising a motor operably coupled to drive a motor shaft and an output drive operably coupled to an output shaft, wherein the motor shaft and the output shaft are mechanically coupled to one another by a transmission system to transfer energy from the motor to the output drive, wherein the motor and motor shaft are coupled to a first housing, wherein the transmission system allows the output shaft to selectively change positions along a circumferential direction relative to a rotational axis of the motor shaft to selectively loosen or tighten a connection of the output drive to the chain at the guide bar.   
     
     
         2 . The chainsaw of  claim 1 , wherein the motor shaft and the output shaft are positioned at separate planes and extending parallel to one another. 
     
     
         3 . The chainsaw of  claim 1 , the drive system comprising:
 a first motor shaft bearing coupled to the motor shaft and the first housing; and   a second motor shaft bearing coupled to the motor shaft and a second housing.   
     
     
         4 . The chainsaw of  claim 3 , the drive system comprising:
 an output shaft bearing coupled to the output shaft and the second housing.   
     
     
         5 . The chainsaw of  claim 1 , the transmission system comprising a plurality of gears operably connecting the motor shaft to the output shaft. 
     
     
         6 . The chainsaw of  claim 5 , wherein the plurality of gears forms a compound gear assembly. 
     
     
         7 . The chainsaw of  claim 5 , wherein the plurality of gears forms a reduction gear assembly, the reduction gear assembly comprising between a 1.5:1 gear reduction and a 3:1 gear reduction. 
     
     
         8 . The chainsaw of  claim 5 , wherein the plurality of gears is positioned at a second housing. 
     
     
         9 . The chainsaw of  claim 5 , the transmission system comprising:
 a first gear coupled to the motor shaft;   a second gear coupled to the output shaft, wherein the first gear and the second gear are meshed to one another.   
     
     
         10 . The chainsaw of  claim 9 , the transmission system comprising:
 a third gear coupled to the output shaft, wherein the third gear is co-rotational with the second gear.   
     
     
         11 . The chainsaw of  claim 1 , the chainsaw comprising:
 a frame at which the guide bar and the first housing are attached, wherein the first housing and the rotational axis of the motor shaft is fixed relative to the frame, and wherein the output shaft is allowed to selectively change positions along the circumferential direction relative to the rotational axis of the motor shaft.   
     
     
         12 . The chainsaw of  claim 1 , the chainsaw comprising:
 a tensioner mechanism comprising a plurality of drive accessories operably coupling a user interface to a second housing to actuate the second housing along the circumferential direction relative to a rotational axis of the motor shaft.   
     
     
         13 . The chainsaw of  claim 12 , wherein the plurality of drive accessories forms a worm gear, worm shaft, and lead screw configured to translate rotational movement of the user interface to rotation of the second housing along the circumferential direction. 
     
     
         14 . The chainsaw of  claim 1 , the chainsaw comprising:
 a lubrication system comprising a reservoir at which a lubricant is containable, the lubrication system comprising a pump assembly at which the reservoir is releasably attachable to the pump assembly;   a gear assembly operably coupling the lubrication system to the transmission system to transmit energy from the motor to drive the pump assembly.   
     
     
         15 . The chainsaw of  claim 14 , wherein selectively changing positions of the output shaft along the circumferential direction relative to the rotational axis of the motor shaft changes a position of the lubrication system along the circumferential direction. 
     
     
         16 . The chainsaw of  claim 14 , the pump assembly comprising a pump body, the pump body comprising an inlet at which the reservoir is selectively attachable to provide a lubricant to the pump body, the pump body comprising an outlet through which the lubricant is provided to the guide bar through a conduit attached to the outlet. 
     
     
         17 . A drive system for a chainsaw, the drive system comprising:
 a motor shaft, wherein the motor shaft is configured to rotate relative to a first rotational axis extending through the motor shaft;   a motor operably coupled to drive the motor shaft;   a first housing, wherein the motor and the motor shaft are operably coupled to the first housing;   an output shaft, wherein the output shaft is configured to rotate relative to a second rotational axis extending through the output shaft, wherein the output shaft is separate from the motor shaft;   an output drive operably coupled to the output shaft; and   a transmission system, wherein the motor shaft and the output shaft are operably coupled to one another by the transmission system to transfer energy from the motor to the output drive, wherein the transmission system allows the second rotational axis at the output shaft to selectively change positions along a circumferential direction relative to the first rotational axis of the motor shaft.   
     
     
         18 . The drive system of  claim 17 , the drive system comprising:
 a first motor shaft bearing coupled to the motor shaft and the first housing; and   a second motor shaft bearing coupled to the motor shaft and a second housing.   
     
     
         19 . The drive system of  claim 18 , the drive system comprising:
 an output shaft bearing coupled to the output shaft and the second housing.   
     
     
         20 . The drive system of  claim 17 , the transmission system comprising:
 a first gear coupled to the motor shaft, the first gear co-rotational with the motor shaft relative to the first rotational axis;   a second gear coupled to the output shaft, the second gear co-rotational with the output shaft relative to the second rotational axis, wherein the first gear is operably coupled to transmit energy to the output shaft through the second gear.